Background and Summary of Significant Accounting Policies - Correction of Immaterial Errors (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Jan. 01, 2021
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Accounts receivable	$ 1,318	$ 1,508
Assets	34,018	45,612
Accounts payable	1,134	1,044
Accumulated deficit	$ (17,907)	(7,609)
Correction of Error from Understatement of Revenues and Network Expenses Prior to 2021
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Accounts receivable		31
Assets		31
Accounts payable		94
Liabilities		$ 94
Accumulated deficit			$ 63